Yet another change… Decided to repurpose the TC Sounds 18” drivers into some kind of subwoofer/s. In hindsight I would have bought the Ultra 5400’s had known about them at the time of purchase. So that leave me looking for a woofer like replacement.

To my surprise the 18” drivers did not do what some thought, and there was no issues controlling x-max, in fact they barely moved, and that is part of the reason for turning the Pro 5100’s into sub drivers.

Following along the lines of several others, I am leaning towards the multiple driver route, and was thinking about 2 or 4 drivers per side in a dipole woofer (“Butt Crack” from several pages back) and also here http://www.linkwitzlab.com/woofer.htm where the idea began.

I think the surround of the pro driver may be too heavy for OB and limiting the excursion.

Nice Qts @ .48 means not a lot eq needed while not being too flappy and resonant. Nice low FS and good price. Too bad they are 4ohms. You would need to use a good Crown or QSC that can handle 2 Ohms or run them in series which is not optimal.

EDIT: Just noticed the Mms, 425g! Ouch, if you believe that this makes a difference. For comparison, my B&C is 96g, but much less xmax and higher FS.

Anyone for four of these per side? (series - parallel)
Fairly cheap before shipping, low sensitivity so SPL wouldn't be crazy over the top.

Spl in a dipole is not thermally limited. You will get the same spl from a 96db 18" driver as you will from a 85db 18" driver, given they have the same xmax.. The first driver will simply use less power to do so.

Four of the 18WUs turned up a few days ago and I got my first listen to the new arrangement.

Glad to report they did exactly what I was hoping for and that was to give the vocals a little more of a bass characteristic.

Rather than just running drivers and amps for the sake of it, I did some A / B testing through the active x-over software. With two copies of the software open I configured one x-over as a three way, and the other as a four way. I left the woofer and tweeter to crossover in the same spot in both configurations.

In the three way I set it up to cover the same band as the mid and mid woofer in the four way. After quite a bit of switching back and forth I came to the conclusion that despite crossing over in the middle of the vocals I prefer the sound of the four way, the 12MU has a very nice sound to it if not overly used, which I guess is very typical of a mid driver.

Due to order timing and Christmas I won’t have the other six 18WUs until next year, but for the time being here is a picture of the prototype speaker. The tweeter isn’t optimally placed, but to reuse the same frame I had to remove one of the 12MUs and turn the tweeter upside down.

Funny you should say that because I was thinking the same thing but while I could just simply turn up the volume to get it to play louder (heaps of headroom left) I prefer the sound of the four drivers. Not sure how to put it but it somehow sounds smoother, no difference in sound but possibly the way the sound is distributed.

Robert from Ground Sound has been helping me get the x-over sorted out (read educating me how to use the software properly) Robert suggested to get the most out of the DCN28 I really needed to step my USB microphone and onboard sound card up a notch. Robert explained to really optimise the x-over I needed to have high quality samples and equipment to work with, pretty much GIGO.

So I have bought a Roland AU 55 Quad Capture Sound Card which arrived a few days ago and I have a new Dayton EMM-6 and cables coming from Parts Express.

Not knowing how to even hook all the equipment up to start proper testing I have been sitting on this expensive piece of software waiting to learn how to use it.

After numerous emails Robert got it through my thick skull how to hook it all up, and once the bits arrive I am set to start meauring.

Not sure I would have even been able to have set it up using my laptop sound card and mic.

I must thank Robert for his patience because the help file in the software is less than decent, and he is trying to fill the gaps.

I am confident once the bits arrive that I have good enough instruction now to at least get a basic capture done. I look forward to seeing some data instead of working off guesswork.

To my ears the sound I now have sounds pretty damn good, but there is still a lot of sorting out to do.